Control means for buttonhole zigzag sewing machine

ABSTRACT

A zigzag sewing machine including means to oscillate the needle at right angle to the work feeding direction, first control means to vary the overstitch width, second control means to vary the stitching direction, third control means to vary needle stitching position, and manual control means for the sewing of buttonholes. The manual control means is operably connected to control cam means to have said control cam means actuated together so as to engage with cooperating follower means at corresponding tracks of said control cam means.

United States Patent Sawada [54] CONTROL MEANS FOR BUTTONHOLE ZIGZAG SEWING MACHINE [72] Inventor: Toshio Sawada, Okazaki, Japan [73] Assignee: Aisin Seiki Kabushiki Kalsha, Aichi Prefi,

Japan [22] Filed: Nov. 9, 1970 [211 App]. No.: 87,877

[30] Foreign Application Priority Data Nov. 10, 1969 Japan ..44/89943 [52] U.S.Cl ..ll2/l58B [51] Int. Cl. DOSb 3/02 [58] FieldofSearch ..ll2/l58 R, 158 A, 158 B,l58C,

[ 1 June 20, 1972 [56] References Cited UNITED STATES PATENTS 3,215,104 l1/1965 Bono ..l12/l58B 3,518,954 7/1970 Blackwood et a] "112/158 B Primary Examiner-Patrick D. Lawson Att0mey-Pierce, Scheffler & Parker [57] ABSTRACT A zigzag sewing machine including means to oscillate the needle at right angle to the work feeding direction, first control means to vary the overstitch width, second control means to vary the stitching direction, third control means to vary needle stitching position, and manual control means for the sewing of buttonholes. The manual control means is operably connected to control cam means to have said control cam means actuated together so as to engage with cooperating follower means at corresponding tracks of said control cam means.

5 Claims, 9 Drawing Figures PKTENTEDJUMO 1972 SHEET 10F 3 lNVENTOR Tosh lo sawadu,

Y 12% CSMLUYQ when ATTORNEY S mtmimuuzo m2 3.670.676 sum 2 or 3 mvsmon Tosh l o S wm P saggbx PML,

v ATTORNEYS PKTENTEDJum I972 3. 670.676

sum 3 or 3 Fig. 40 F/g 4c Fig. 4b Fig. 40

INVENTOR Toshlo sawada,

M ZRQZ CONTROL MEANS FOR BUTTONHOLE ZIGZAG SEWING MACHINE BACKGROUND OF THE INVENTION The present invention relates to a control device for sewing of buttonholes by monitoring the extending length of a buttonhole being produced by means of zigzag sewing machines, while the machine is operating, involving the sewing of a first row of buttonhole zigzag side stitches, first barring stitches, a

second row of buttonhole side stitches, and second or final barring stitches.

There have been known in the art various types of super-automatic or semi-automatic buttonhole stitch sewing machine by any of which the automatic sewing of buttonholes of var-ing and preselectable length is performable in the order of a first row of buttonhole zigzag side stitches, first barring stitches, a second row of buttonhole side stitches, and second barring stitches.

Although the stitching operation may be automatically or semi-automaticallyperformed for sewing the buttonholes by such types of sewing machines, the setting manipulation of their control mechanisms is required prior to start'up of the machine with the aid of the control knob and associated indicating scale or the like. The manipulation will require some experience and complicates the operator's work. Further, lengthwise sizes of the resultant buttonholes are limited in number as to individual types of sewing machine. Also the provision of such scale and its cooperating devices correspondingly complicates the construction of the control device and will reduce the rate of substantial saving of the manufacturing cost.

Generally speaking, the present invention contemplates the presentation of a manipulatable control device of simple structure for zigzag sewing machines, by which any desired length of the resultant buttonholes may be obtained from a minimum to a maximum no matter what the desired length may be, by monitoring the extending length of a buttonhole during the sewing operation.

SUMMARY OF THE INVENTION With the foregoing objects in view, the invention involves the provision of a control device for sewing buttonholes of any desired length by monitoring the extending length of the buttonholes while the machine is operating, said control device comprising first, second and third control cams all fastened to a shaft manually rotative by manual control means outside the housing of the machine within convenient reach of the operator and having cooperating first, second and third cam followers operably connecting the same with the control means of the sewing machine for the adjustment of the stitching position, the overstitch width, and the stitching direction. Each of the cams is provided with a series of cam surfaces in successive steps designed to have the control means moved to and maintained at their operating positions, whereby to enable the manual actuation of the control means for sewing the buttonhole in the order of first buttonhole side stitches in a first direction, first buttonhole barring stitches, second buttonhole side stitches in the opposite direction and second barring stitches in the same manner as the first barring stitches. The length of the resultant buttonholes may be continuously varied from minimum to maximum whatever variation is required by manually rotating the knob or the like outside the housing of the machine.

Besides, one of the cam means may additionally serve, in the idle position of the other cam means, for the adjustment of the stitching position during normal operation of the sewing machine.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a buttonhole sewing device for zigzag sewing machines, being constructed in accordance with the principles of the invention,

FIG. 2 is a perspective view of separated parts of the device of FIG. 1, in which their relationship to one another is shown,

FIG. 3 is a perspective view of a cam of the device,

FIG. 4a to 4d are detail views of respective stages of the buttonhole working,

FIG. 5a and 5b are respective detail views in enlarged scale taken along the line V V in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now particularly to the drawings, FIG. 1, the numeral 1 denotes the needle bar of a conventional zigzag sewing machine carrying a sewing needle and mounted for reciprocation in the vertical direction in a needle bar frame or holder 2, as indicated by the double arrow a, said frame being in turn mounted for oscillation at a right angle to the work feeding direction about a fixed pivot or spindle 3 supported by the frame of the machine, as indicated by the double arrow b in the drawing. Reciprocation of the needle is effected in known manner by coupling of the needle bar 1 with the main drive shaft or an arm shaft 4 of the sewing machine via a crank 5 and link 6 connected to a journal pin 7 affixed to the bar 1. Linked to the needle bar frame 2 is one end of a control bar 8 whose opposed end is in turn linked to another link 9 by a journal pin 11 as shown partially. The link 9 is connected to a known knob or dial (not shown) placed outside the housing within a convenient reach of the operator to manually change the overstitch width even though while the machine is operating. The control bar 8 is normally urged to the left by the action of a tension spring 10 having one end thereof anchored to the control bar and the other end to a suitable stationary part of the frame. The journal pin 11 carries on its extension a roll 12 freely rotatable thereon and urged into sliding engagement with a swingable guide lever 13 rotatably supported upon a pin 14 fixed to an arm or bracket 14a fastened to the frame of the machine. The swing of the lever 13 causes the bar frame 2 to swing through the control bar 8 as will be clarified hereinbelow. The roll 12 can be adjusted to the pivot 14 about which the swingable guide level 13 oscillates. When the guide lever 13 oscillates about the pivot 14, it transmits oscillation through the roll 12 to the control bar 8 and in turn the needle bar 1 is oscillated. The length of the reciprocation of the control bar 8 is governed by the oscillation of the roll 12 relative to pivot 14, which may be varied by means of known knob or dial (not shown) outside the housing within a convenient reach of the operator, When the roll 12 is moved upward until it is directly over the pivot 14, no movement will be imparted to the control bar 8 whereby the needle does not swing and usual straight line stitches may result.

A worm 15 fast on the main drive shaft 4 meshes with a worm gear 16 being in integral with a gear 17 as clearly shown in FIG. 2. The gear 17 in turn meshes with another gear 18, the shaft 23 of which extends upwardly in the drawing and carries a cam 19 through a flange 22 fast on the shaft by means of a set screw 24. Although the cam 19 is a free sliding fit upon the hub 28 of the flange with the center 27, the shaft 23 transmits motion to the cam 19 through engagement of a projection or pin 26 on the flange with a corresponding small hole 25 on the cam 19. A follower lever 20 swingable about a spindle 21 engages the cam 19 at its extremity end. To the lever 20 is so fastened a member 29 that a hole 30 of the member is in alignment with and diametrically equal to the follower lever's hole 32 into which the pin 21 is loosely received so as to allow the member and lever 20 to swing together about the pin 21 as the cam rotates. Another cam 33 being in integral with a gear 34 is a free running fit on the shaft 23, with the cam surface of which engages a screw 35 screwed to the member 29. The member 29 rotatably supports in its hole 36 a pin 37, at the lower end of which are formed two cam surfaces 37ab and 370 as shown particularly in FIG. 5a and FIG. 5b, to engage with a pin 38 afixed to the lever 13, so that a rotation of the pin 37 about its axis will selectively cause the cam surfaces 37ab or 37c to engage with the pin 38 as will hereinbelow be more fully described.

From the preceding, it will be noted that the follower 20 is normally urged into contact with the cam 19 by the action of the tension spring through the control bar 8, pin 1 1, roll 12, pin 38, cam surface 37ab or 370 and pin 37. Further it will be noted that the rotation of the cam 19 will cause the needle bar 1 to swing so that the zigzag stitch may result. Still further, it should be noted that in the design illustrated, the right-hand stroke or travel of the lever 20 is caused by the periphery of the cam 19 while the reverse or leftward movement is caused by the action of the restoring spring 10, whereby the reverse movement may be limited by the contact of the adjusting stopscrew with the periphery of said another cam 33. As used herein, the term negatively" refers to the manner that the follower lever 20 is given the positive motion in one direction by the surface of the cam 19 while the follower is given the motion in the opposite direction relying upon the spring 10. Both the cam 19 and the cam 33 act negatively relative to the common follower 20 and the cam 19 is used as a master while the cam 33 controls the fall of the follower about the pin 21 in such way that the length of reciprocation of the control bar 8 is controlled by the surface of the cam 33 and in turn the overstitch width is controlled as will herein below be clear. The cam 33 is provided with three series of cam surfaces. One series of them is indicated by the reference characters 330 to 33c and other series are respectively indicated by the reference characters 33a to 33c and 61ab and 61c (shown in FIG. 3). The lift of the cam track 3312 is equal to that of the cam track 33c and is higher than the lift of the cam track 331:. The higher lift of the cam tracks 33a and 33c permits the follower lever 20 to drop a comparatively small amount but a sufficient distance to have the needle bar 1 swung for forming the side stitches of the buttonhole and the lower lift of the cam track 33c permits the lever 20 to have the needle 1 swung a comparatively larger amount for forming the barring stitches of the buttonhole which is produced by the sewing machine.

The cam tracks 33a to 33 cause a lever 39 to move toward their periphery to vary reciprocating direction of the work feed dog (not shown) in the forward or reverse sewing direction as will be clarified as the description proceeds. The lever 39 is oscillatably supported on a pin 41 fast on a base plate B affixed to a suitable stationary part of the machine, on the hub of which is retained another lever in integral relation with the lever 39 with both diametrically reduced ends of the common pin borne by respective holes of the both levers 39 and 40. The purpose of the provision of the lever 40 is that a different type of cam may be placed in place of the cam 19 to automatically vary the reciprocating feed direction of the feed dog as a desired ornamental stitching may require. in case where the said different cam is placed in place of the cam 19, the lever 39 remains idle or inoperative while the lever 40 functions as a follower to the cam to cause a complicated ornamental feed motion of the feed dog. Rotatively mounted upon the end of the lever 39, by the common journal pin 50, is a link 43 to which is in turn rotatively connected an arm 44 of a bellcrank lever 45 rotatively supported on a shaft or spindle 46 fast on the frame of the machine, the remaining arm 47 of said bellcrank lever resiliently engaging at an adjusting screw 51 a further lever 48 rotative on the common spindle 46 by the force of a torsion spring 49 having one end anchored to the arm 44 and having the opposite end anchored to the lever 48 so that the lever 48 may be rotative in the clockwise direction against the force of the spring 49 even though the bellcrank lever 45 is caused to remain stationary by the cam 33 and its followers. The arm 47 is provided at its end an adjusting screw 51 for adjusting the arm 47 relative to the lever 48. There is no reason, except for the sake of a safeguard against the over-running of the lever 45, why the torsion spring should be provided. It should be noted that the bellcrank lever 45 must be so designed that it swings a somewhat larger fixed amount than the maximum of the varying movement of the link amount of a movement preselected prior to the start-up of the buttonhole stitch sewing by manually adjusting a stop screw 530 relative to a cam face 530 or 53b of a guide 53 as hereinbelow described. Rotatively mounted upon the end of the 52 which is not allowed to swing beyond an lever 48 is a link 52 to which is in turn rotatively connected a stitch controller guide 53 of well known construction. Within the controller guide 53 is the slide block (not shown) rotatively connected to an intermediate point of an also well known control lever (not shown), the forked end of which embraces an eccentric (not shown) of the main drive shaft 4 in a manner well known to those skilled in the art. Depending upon the angular position of the guide 53, in respect to its rotating axis 54, the work feed dog of the sewing machine, being operably connected to the lower end opposite the forked end of the lever, has imparted to it varying reciprocating feed movements in the forward or reverse sewing direction, respectively, thereby determining the length of the stitch being sewn by the needle in cooperation with a loop taker (not shown), in a well known manner.

A tension spring 54a, having one end connected to the guide 53 and having the opposite end connected to the frame of the sewing machine, resiliently urges the lever 39 into contact with the cam 33. However, when the lever 45 swings in the counter-clockwise direction in the drawing, the torsion spring 49 overcomes the tension spring 540 through the link 52. A series of the cam tracks 3 to 33c is so designed that the rotation of the cam 33 causes the guide 53 to be in successive steps adjusted to and maintained at three positions following the order of forward feed, almost zero feed, and reverse feed positions by the cam 33 and via lever 39, link 43, bellcrank lever 45, lever 48 and link 52. A lever 55 is rotatively supported on the common pin 41 fast on the base plate B and embraces within its forked end a projection or pin 57 on an arm 58 affixed by a set screw 59 to the pin 37 and has its pin 60 engaged with a cam groove 61 formed on the rear surface of the gear 34 as illustrated in FIG. 3. The rotation of the gear 34 will cause an angular movement of the lever 55, through the cam groove 61 and the pin 60, whose forked end in turn moves so as to rotate the arm 58 of the pin 37. Through the rotation of the pin 37, the series of the cam surfaces 37ab and 37c formed at its lower end produces a rise or fall of the lever 13 about the pivot 14 through the pin 38. This rise or fall will cause the needle bar to convert its sewing position on the work through the control bar 8, from a first row of buttonhole zigzag side stitches to a second row of buttonhole side stitches and vice versa.

A segment gear 62 affixed to a shaft 63 rotatively supported on the base plate B meshes with the gear 34. The shaft 63 protrudes beyond the housing of the machine and fits with a control knob or disk 64 within convenient reach of the operator. The knob 64 is provided on its face with a series of marks a to c and a mark A and a mark R. Manipulation of the knob 64 to rotate it a required amount in any direction by reading the marks in contrast with a suitable mark (not shown) on the housing face, one of cam tracks of each of the three series of the cam 33 may selectively be occupied by the correspondingly related followers. The segment gear 62 is provided with a well known clamping mechanism consisting of a small ball 62a, leaf spring 62b, fastened to the gear by means of a set screw 62c and a small hole 62d in slidable fitable relation with the ball. A recess (not shown) of corresponding size to partially receive the ball therein is provided in the surface of the stationary part of the machine closely adjacent to the rear face of the gear 62, so that the operator becomes aware of the clamping of the movable gear while the ball can be slipped out of the recess by rotating the knob 64 against the situation having been presented.

During the operation of the sewing machine, the cam 19 is driven by the main drive shaft 4 via the worm and worm gears 15 and 16, spur gears 17 and 18 and shaft 23, whereby to oscillate the lever 20 about its axis 21. The oscillation of the lever is in turn imparted, via the member 29, spindle or pin 37, slidable guide lever 13, control bar 8 upon the needle bar 1 during each stitching cycle or zigzag stitches sewn by the machine.

In dependency on the cam tracks of the cam 19, and its rotating speed, the swing or oscillation of the needle bar is in synchronism with the vertical reciprocation of the needle bar.

The cam 33 is a free running fit on the shaft 23 and is manually rotatable by manipulating the knob 64, whereby any continuous variation in length of the resultant buttonhole side stitches can be obtained from a minimum to a maximum and stitching position and direction may readily be changed to complete the buttonhole stitching cycle.

In case where the track 33a of the cam 33 is adjusted and maintained at a working position to come into contact with the adjusting stop screw 35 of the member 29 by the knob 64 and via the segment gear 62 and spur gear 34, the reverse or leftward movement of the member 29 is limited by the track 33a so as to impart to the needle bar 1 an oscillating amplitude or overstitch width suitable for the sewing of the first side stitches a of the buttonhole to be produced as shown in FIG. 4a. At the same time the track 33a is in the working position, other track 330' comes in contact with the lever 39 and the guide 53 of the stitch controller is maintained at an angular position to maintain a feed stroke or stitching length in the forward sewing direction of the machine according to the example shown and further described in the following. In this condition, the fall of the lever 39 is sufficient to permit the guide 53 to angularly oscillate by the spring 540 until the surface 53a comes into contact with a well known stopper screw 530 which may be displaceable by manipulation along the double arrow c in relation to a desired and preselected amount of the feed motion of the feed dog. It will be noted that when the cam track 53a comes into contact with the stopper screw 53c, the lever 39 remains idle or inoperable apart from the cam track 33a while the other cam face 53b may come into contact with the stopper screw 53c and be maintained at this position by continuing function of the other cam track of the cam 33 via the lever 39, link 43, bellcrank lever 45, torsion spring 49 and link 52. The over-running of the lever 39 is consumed in torsion of the spring 49 and the safe-guard is thus secured against breakage which would otherwise happen in the mechanism. In the above described operation, sewing of the righthand row a of buttonhole stitches in FIG. 4a is effected in the forward direction indicated by arrow.

When secondly, the knob is rotated the angular amount from the mark a to the mark b on the knob so as to cause the cam track 33b to come into contact with the stop screw 35, the fall of the member 29 increases as compared with the previous fall, whereby the barring stitch b shown in FIG. 4b is produced. At the same time that the cam track 33b comes into contact with the screw 35, the other cam track 33b comes into contact with the lever 39, the lift of which is higher than that of the track 33a and is suitable for maintaining the guide 53 at the middle position, whereby the feed stroke of the feed dog is reduced almost to zero. In this condition, the barring stitches b is sewn as shown in FIG. 4b.

Thirdly, the knob 64 is rotated in the same direction until the cam track 33c comes into contact with the screw 35 by reading the mark c on the knob face. Since the cam lift of the track 33c is equal to that of the track 33a, the rise of the member 29 again is rendered equal to that which produced the first side stitch sewing as shown in FIG. 4a. At the same time that the track 33c comes into contact with the screw 35, the track 33c comes into contact with the lever 39, the lift of which is further higher enough to further rotate the guide 53 upwardly in the drawing so that the reverse feeding of the feed dog is then produced via the known mechanism previously referred to. At the same time that the cam track 33c comes into contact with the lever 39, the remaining cam track 61c timingly comes into engagement with the projection 60 on the lever 55, and the track 6lab previously occupied by the projection 60 ceases to function as a cam, whereby the lever 55 is oscillated about the pin 41 in the clockwise direction in the ex ample shown, and the pin 37 is, in turn, axially rotated in the counter-clockwise direction through the forked end of the lever 55, pin 57 and the arm 58 fast on the pin 37. The oscillation of the pin 37 is in position shifted toward the left in the example shown by the axial rotation of the pin 37 by reason of the fact that the previous engagement of the cam surface 37ab has been changed to the engagement of the other cam surface 37c with the pin 38 of the arm or guide 13, and the lift of the cam surface 370 is designed to be lower than that of the cam surface 37ab. The stitching position of the needle bar 1 is thus shifted to the left as shown in FIG. 4c so that the left side stitches of the buttonhole may be produced as indicated by the reference character c in FIG. 4c.

Finally, the knob is rotated in the adverse direction until the mark h on the knob again comes to the mark on the housing (not shown). The rotation of the knob causes the tracks 33b, 33b and 6lab to again come into contact with their respective followers. In this condition, the second barring stitches b is produced in the same manner as the first barring stitches as shown in FIG. 4d, and one cycle of the buttonhole stitching is thus completed.

The marks A and R are provided for the purpose of reading in case where the followers of the cam tracks are in their respective idle positions or the other position to produce specific stitches not contemplated by the invention. The description of the marks may accordingly be alleviated.

What is claimed is:

1. In a zigzag sewing machine including means to oscillate the needle at right angle to the work feeding direction, first control means to vary the overstitch width, second control means to vary the stitching direction, third control means to vary needle stitching position, and manual control means of the sewing of buttonholes comprising:

1. cam means driven by the main drive shaft of the sewing machine,

2. cooperating follower means operably connecting said cam means to said means to oscillate the needle,

3. fust, second and third control cam means integral with one another and manipulative by said manual control means,

4. cooperating first, second and third cam follower means operably connecting said control cam means with said first, second and third control means respectively,

said control cam means having respectively a series of successive cam tracks designed to have said corresponding control means to be moved to and maintained at working positions such as to effect the sewing of first buttonhole side stitches in a first direction, of first buttonhole barring stitches and second buttonhole side stitches in an opposite direction, and of second buttonhole barring stitches,

said manual control means being operably connected to said control cam means to have said control cam means actuated together so as to engage with cooperating follower means at corresponding tracks of said control cam means.

2. In a buttonhole zigzag sewing machine as claimed in claim 1, said first cam follower means being associated with said both cam means driven by the main drive shaft and said first cam means so as to negatively function as a common cam follower relative to said both cam means in the same side of said both cam means, whereby fall of said follower is limited by said first cam means.

3. In a buttonhole zigzag sewing machine as claimed in claim 1, said first cam follower means carrying another cam means actuated by said third cam follower means while upon the other hand actuating said third control means to vary needle stitching position.

4. In a buttonhole zigzag sewing machine as claimed in claim 1, said second cam follower means being connected to the stitch controller guide of conventional construction, so as to vary stitching direction on the work.

5. In a buttonhole zigzag sewing machine as claimed in claim 1, said all three control cam means being in integral relation one another and being supported upon a common shaft manually rotative by a knob or disk outside the housing of the sewing machine within convenient reach of the operator.

m 1: m w s 

1. In a zigzag sewing machine including means to oscillate the needle at right angle to the work feeding direction, first control means to vary the overstitch width, second control means to vary the stitching direction, third control means to vary needle stitching position, and manual control means of the sewing of buttonholes comprising:
 1. cam means driven by the main drive shaft of the sewing machine,
 2. cooperating follower means operably connecting said cam means to said means to oscillate the needle,
 3. first, second and third control cam means integral with one another and manipulative by said manual control means,
 4. cooperating first, second and third cam follower means operably connecting said control cam means with said first, second and third control means respectively, said control cam means having respectively a series of successive cam tracks designed to have said corresponding control means to be moved to and maintained at working positions such as to effect the sewing of first buttonhole side stitches in a first direction, of first buttonhole barring stitches and second buttonhole side stitches in an opposite direction, and of second buttonhole barring stitches, said manual control means being operably connected to said control cam means to have said control cam means actuated together so as to engage with cooperating follower means at corresponding tracks of said control cam means.
 2. cooperating follower means operably connecting said cam means to said means to oscillate the needle,
 2. In a buttonhole zigzag sewing machine as claimed in claim 1, said first cam follower means being associated with said both cam means driven by the main drive shaft and said first cam means so as to negatively function as a common cam follower relative to said both cam means in the same side of said both cam means, whereby fall of said follower is limited by said first cam means.
 3. In a buttonhole zigzag sewing machine as claimed in claim 1, said first cam follower means carrying another cam means actuated by said third cam follower means while upon the other hand actuating said third control means to vary needle stitching position.
 3. first, second and third control cam means integral with one another and manipulative by said manual control means,
 4. cooperating first, second and third cam follower means operably connecting said control cam means with said first, second and third control means respectively, said control cam means having respectively a series of successive cam tracks designed to have said corresponding control means to be moved to and maintained at working positions such as to effect the sewing of first buttonhole side stitches in a first direction, of first buttonhole barring stitches and second buttonhole side stitches in an opposite direction, and of second buttonhole barring stitches, said manual control means being operably connected to said control cam means to have said control cam means actuated together so as to engage with cooperating follower means at corresponding tracks of said control cam means.
 4. In a buttonhole zigzag sewing machine as claimed in claim 1, said second cam follower means being connected to the stitch controller guide of conventional construction, so as to vary stitching direction on the work.
 5. In a buttonhole zigzag sewing machine as claimed in claim 1, said all three control cam means being in integral relation one another and being supported upon a common shaft manually rotative by a knob or disk outside the housing of the sewing machine within convenient reach of the operator. 